Shareholders' Equity (Details) - USD ($)	1 Months Ended		3 Months Ended			9 Months Ended		54 Months Ended
	Oct. 28, 2016	Aug. 31, 2015	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Nov. 30, 2014	Apr. 30, 2012
Common Stock Programs
Shares purchased (in shares)								88,400,000
Total cost of shares purchased						$ 1,051,000,000		$ 7,000,000,000
Weighted average shares outstanding
Shares for basic earnings per share (in shares)			267,500,000		280,900,000	269,100,000	283,200,000
Common stock equivalents (in shares)			2,100,000		2,900,000	1,900,000	2,700,000
Shares for diluted earnings per share (in shares)			269,600,000		283,800,000	271,000,000	285,900,000
Number of shares excluded from the calculation of diluted earnings per share (in shares)			0
Decrease on prepaid pension				$ 267,000,000
Share Repurchase Program of 2014 [Member]
Common Stock Programs
Share repurchase authorization limit (up to)									$ 5,000,000,000.0
Share repurchase, remaining authorization limit (shares)			$ 3,000,000,000			$ 3,000,000,000		$ 3,000,000,000
2012 - Share Repurchase Program [Member]
Common Stock Programs
Share repurchase authorization limit (up to)										$ 5,000,000,000.0
Shares purchased (in shares)			2,700,000		6,300,000	10,400,000	11,700,000
Average price per share of stock repurchased (in usd per share)			$ 110.26		$ 95.75	$ 101.16	$ 98.00
Total cost of shares purchased		$ 5,000,000,000	$ 301,000,000		$ 600,000,000	$ 1,100,000,000	$ 1,150,000,000
Subsequent Event [Member] | 2012 - Share Repurchase Program [Member]
Common Stock Programs
Shares purchased (in shares)	128,000
Average price per share of stock repurchased (in usd per share)	$ 112.00
Total cost of shares purchased	$ 14,300,000